In a food processor, pulse walnuts and sugar together until finely ground. Add butter and pulse until mixture looks like moist sand. Press onto bottom and 1 inch up side of 9-inch springform pan. Bake for 10 minutes. Cook on wire rack for 10 minutes.
Beat cream cheese, granulated sugar and brown sugar in a large mixer bowl until fluffy. Beat in eggs, pumpkin and evaporated milk. Add cornstarch, cinnamon and nutmeg; beat well. Pour into crust. Bake for 55 to 60 minutes or until edge is set but center still moves slightly.